# coding=utf-8

import cv2
import numpy
import time


class CaptureManager(object):
    def __init__(self, capture, previewWindowManager=None, shouldMirrorPreview=False):
        self._vidwoWriter = None;
        self._previewWindowManager = previewWindowManager
        self._shouldMirrorPreview = shouldMirrorPreview
        self._capture = capture
        self._channel = 0
        self._enteredFrame = False
        self._frame = None
        self._imageFilename = None
        self._videoFilename = None
        self._videoEncoding = None
        self._videoWriter = None

        self._startTime = None
        self._framesElapsed = numpy.long(0)
        self._fpsEstimate = None

    @property
    def channel(self):
        return self._channel

    @channel.setter
    def channel(self, value):
        if self._channel != value:
            self._channel = value
            self._frame = None

    @property
    def frame(self):
        if self._enteredFrame and self._frame is None:
            _, self._frame = self._capture.retrieve();
            return self._frame

    @property
    def isWritingImage(self):
        return self._imageFilename is not None

    @property
    def isWritingVideo(self):
        return self._videoFilename is not None

    def enterFrame(self):
        """Capture the next frame, if any."""
        # But first, check that any previous frame was exited.
        assert not self._enteredFrame, \
            'previous enterFrame() had no matching exitFrame()'

        if self._capture is not None:
            self._enteredFrame = self._capture.grab()

    def exitFrame(self):
        """Draw to the window. Write to files. Release the Frame."""
        # Check whether any grabbed frame is retrievable.
        # The getter may retrieve and cache the frame.
        if self.frame is None:
            self._enterFrame = False
            return

        # Update the FPS estimate and related variables.
        if self._framesElapsed == 0:
            self._startTime = time.time()
        else:
            timeElapsed = time.time() - self._startTime;
            self._fpsEstimate = self._framesElapsed / timeElapsed
        self._framesElapsed += 1

        # Draw to the window, if any.
        if self._previewWindowManager is not None:
            mirroredFrame = numpy.fliplr(self._frame).copy()
            self._previewWindowManager.show(mirroredFrame)
            # self._previewWindowManager.show( self._frame )
        else:
            self._previewWindowManager.show(self._frame)

        # Write to the image file, if any.
        if self.isWritingImage:
            cv2.imwrite(self._imageFilename, self._frame)
            self._imageFilename = None

        # Write to the video file, if any.
        self._writeVideoFrame()

        # Release the frame.
        self._frame = None
        self._enteredFrame = False;

    def writeImage(self, filename):
        """Write the next exited frame to an image file."""
        self._imageFilename = filename;

    def startWritingVideo(self, filename, encoding=cv2.VideoWriter_fourcc('I', '4', '2', '0')):
        """Start writing exited frames to a vidwo file."""
        self._videoFilename = filename;
        self._videoEncoding = encoding;

    def stopWritingVideo(self):
        """Stop writing eited frames to a video file."""
        self._videoFilename = None;
        self._videoEncoding = None;

    def _writeVideoFrame(self):
        if not self.isWritingVideo:
            return
        if self._videoWriter is None:
            fps = self._capture.get(cv2.CAP_PROP_FPS);
            if fps == 0.0:
                # The capture's FPS is unknown so use an estimate.
                if self._framesElapsed < 20:
                    # Wait until more frames elapse so that the estimate is more stable.
                    return
                else:
                    fps = self._fpsEstimate
            size = (int(self._capture.get(cv2.CAP_PROP_FRAME_WIDTH)),
                    int(self._capture.get(cv2.CAP_PROP_FRAME_HEIGHT)))
            self._videoWriter = cv2.VideoWriter(self._videoFilename, self._videoEncoding, fps, size)
        self._videoWriter.write(self._frame)


class WindowManager(object):
    """
k
    """
    def __init__(self, windowName, keypressCallback=None):
        self.keypressCallback = keypressCallback
        self._windowName = windowName
        self._isWindowCreate = False

    @property
    def isWindowCreated(self):
        """

        :return:
        """
        return self._isWindowCreate

    def createWindow(self):
        cv2.namedWindow(self._windowName)
        self._isWindowCreate = True

    def show(self, frame):
        cv2.imshow(self._windowName, frame)

    def destroyWindow(self):
        cv2.destroyWindow(self._windowName)
        self._isWindowCreate = False

    def processEvent(self):
        keycode = cv2.waitKey(1)
        if self.keypressCallback is not None and keycode != -1:
            # Discard any non-ASCII info ecdoded by GTK.
            keycode &= 0xFF
            self.keypressCallback((keycode))
